The ombudsman of Russia's second largest city, St. Petersburg, has accused city authorities of "provoking" unsanctioned protests.

An estimated 1,560 people were detained at anticorruption demonstrations nationwide on June 12 that were organized by opposition leader Aleksei Navalny, including more than 500 in St. Petersburg.

Aleksandr Shishlov wrote on his website that "hundreds of people, including teenagers, journalists, observers and other people, who did not pose any social threat" were detained during the anticorruption protests in the city on June 12.

"It is not only those who organized and took part in the unsanctioned action who bear responsibility but also the executive organs that refused to permit the public event," Shishlov wrote.

The authorities "yet again demonstrated an unwillingness and inability to find a lawful solution that would provide citizens' constitutional right of freedom of assembly," he said. "Police were again placed in conditions that make it difficult to preserve public order and lead to the violation of human rights."

Most of the detainees had been released by June 13. However, many have been reportedly mistreated while in police detention.

Rights watchdog Amnesty International said on June 14 that many of the protesters in Moscow and St. Petersburg had been "subjected to cruel and degrading treatment in police detention over the past 48 hours."

"Hundreds of peaceful protesters in Moscow and St. Petersburg were locked up in police stations overnight, in plainly degrading conditions, crowded cells with little or no food, bedding or easy access to sanitation,” said Denis Krivosheev, Deputy Director for Europe and Central Asia at Amnesty International.

The United States, the European Union, and other human rights groups have condemned the detentions.

Navalny called for the nationwide rallies to protest what he alleges is a system of corruption and cronyism presided over by President Vladimir Putin.